Water melts from a liquid to a solid at 0°C, and it boils from a liquid to a gas at 100°C. The average temperature on Earth is 14°C which means that water is usually a liquid on Earth. Liquid water is REALLY important for life on Earth.
Methane melts from a liquid to a solid at -183°C (yes, minus), and it boils from a liquid to a gas at -162°C. Titan, which is the largest moon of Saturn, has an average temperature of -179°C which means that Titan is really cold and that methane is usually a liquid on Titan.
So just like Earth has a water cycle, Titan has a methane cycle with methane clouds and everything – cool.

